This change fixes the circuitry responsible for enforcing the uniqueness
of 'External_Tag attribute values. Previously uniqueness was checked at
type elaboration time only for types that have an explicit External_Tag
attribute definition clause. However we must also account for the fact
that the default external tag for a type without any such clause may clash
with that of a type with an explicit clause that has been elaborated
previously.
The elaboration of the following unit must cause PROGRAM_ERROR to be raised:
$ gnatmake -z -gnatws default_explicit_ext_tag.ads
$ ./default_explicit_ext_tag
raised PROGRAM_ERROR : duplicated external tag "DEFAULT_EXPLICIT_EXT_TAG.T2"
package Default_Explicit_Ext_Tag is
type T1 is tagged null record;
for T1'External_Tag use "DEFAULT_EXPLICIT_EXT_TAG.T2";
type T2 is tagged null record;
end Default_Explicit_Ext_Tag;
Tested on x86_64-pc-linux-gnu, committed on trunk
2014-07-17 Thomas Quinot <qui...@adacore.com>
* exp_disp.adb (Make_DT, Make_VM_TSD): Do not omit Check_TSD
call for types that do not have an explicit attribute definition
clause for External_Tag, as their default tag may clash with an
explicit tag defined for some other type.
Index: exp_disp.adb
===================================================================
--- exp_disp.adb (revision 212640)
+++ exp_disp.adb (working copy)
@@ -6,7 +6,7 @@
-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2013, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
@@ -6209,9 +6209,8 @@
end if;
end if;
- -- If the type has a representation clause which specifies its external
- -- tag then generate code to check if the external tag of this type is
- -- the same as the external tag of some other declaration.
+ -- Generate code to check if the external tag of this type is the same
+ -- as the external tag of some other declaration.
-- Check_TSD (TSD'Unrestricted_Access);
@@ -6226,16 +6225,16 @@
if not No_Run_Time_Mode
and then Ada_Version >= Ada_2005
- and then Has_External_Tag_Rep_Clause (Typ)
and then RTE_Available (RE_Check_TSD)
and then not Debug_Flag_QQ
then
Append_To (Elab_Code,
Make_Procedure_Call_Statement (Loc,
- Name => New_Occurrence_Of (RTE (RE_Check_TSD), Loc),
+ Name =>
+ New_Occurrence_Of (RTE (RE_Check_TSD), Loc),
Parameter_Associations => New_List (
Make_Attribute_Reference (Loc,
- Prefix => New_Occurrence_Of (TSD, Loc),
+ Prefix => New_Occurrence_Of (TSD, Loc),
Attribute_Name => Name_Unchecked_Access))));
end if;
@@ -6810,12 +6809,10 @@
Expressions => TSD_Aggr_List)));
-- Generate:
- -- Check_TSD
- -- (TSD => TSD'Unrestricted_Access);
+ -- Check_TSD (TSD => TSD'Unrestricted_Access);
if Ada_Version >= Ada_2005
and then Is_Library_Level_Entity (Typ)
- and then Has_External_Tag_Rep_Clause (Typ)
and then RTE_Available (RE_Check_TSD)
and then not Debug_Flag_QQ
then
